Network systems have been proposed that have an element management system (EMS), which manages a group of network elements (NEs), and a network management system (NMS) encompassing multiple EMSs, where various settings of an NE in a layer 2 domain are manually performed through the EMS (see, for example, Japanese Laid-Open Patent Publication Nos. 2002-51076 and 2002-252636).
In the layer 2 network, when a given guarantee of bandwidth is performed for each VLAN, in the technology disclosed in Japanese Laid-Open Patent Publication Nos. 2002-51076 and 2002-252636, the EMS manages multiple NEs and changes the minimum guaranteed communication rate (committed information rate (CIR)). When fixed layer 2 services such as video delivery and VoIP services are performed over an established given bandwidth, VLAN path management using the current EMS is suitable.
If the guarantee of bandwidth between user points and cloud service points is considered, statically fixed guaranteed bandwidths alone may not suffice and when an application that utilizes a large number of cloud service CPUs is executed, the required communication volume temporarily increases and further when operations such as database backup or uploading arise, the required amount of bandwidth also temporarily increases.
However, with the conventional technologies, not all of the relay apparatuses on the OVC can instantaneously determine whether CIR changes are permissible. Since CIR changes cannot be reflected at all of the relay apparatuses on the OVC, even if the number of servers or bandwidths for utilization of a cloud service from a specific user point are temporarily increased, the minimum guaranteed amount of bandwidth that is necessary cannot be easily changed. As a result, consequent to a bottleneck of bandwidth, cases arise in which the utilization method of a cloud service is limited.
In a first conventional technology, configuration is such that after bandwidth is requested of a management server performing centralized management, the management server surveys the network bandwidth and secures available bandwidth; thus, much time is consumed from the time when a demand for required bandwidth arises until the bandwidth is actually secured. In a second conventional technology, configuration is such that wavelength paths are reserved. When a wavelength path is reserved, the IP address is designated and a path is reserved; consequently, points are limited to a ratio of 1:1 and the guarantee of bandwidth for paths between multiple points is not possible.